Untwisting mechanism

ABSTRACT

A device and method for partially untwisting a twisted continuous filament tow during unwinding by rotating a spool, upon which the continuous filament is wound, about an axis at an angle to the axis about which the continuous filament bundle is unwinding.

United States Patent Zimmermann, Jr.

UNTWISTING MECHANISM Inventor: Ernest H. Zimmermann, Jr.,

Webster, Mass.

Assignee: Brunswick Corporation, Skokie, 111.

Filed: Oct. 29, 1973 Appl. No.: 410,955

U.S. Cl. 57/1 UN, 57/2.3, 57/156 Int. Cl D01g 1/06 Field of Search 57/1 R, 1 U, 2.3, 2.5, 57/34 R, 36, 50, 59, 62, 127.5, 127.7, 156; 242/43.l

References Cited UNITED STATES PATENTS Spaulding 57/2.3 X Fehrer 57/50 X 1 Feb. 18, 1975 3,123,968 3/1964 Flanigan 242/431 X 3,154,908 11/1964 Cilker et all. 3,707,836 1/1973 Lovett 57/1 UN FOREIGN PATENTS OR APPLICATIONS 898,688 6/1962 Great Britain 57/25 Primary Examiner-Donald E. Watkins Attorney, Agent, or Firm-Donald S. Olexa, John G. Heimovics; John J. Connors [57] ABSTRACT A device and method for partially untwisting a twisted continuous filament tow during unwinding by rotating a spool, upon which the continuous fiiament is wound, about an axis at an angle to the axis about which the continuous filament bundle is unwinding.

24 Claims, 4 Drawing Figures 1 UNTWISTING MECHANISM BACKGROUND OF THE INVENTION l. Field of the Invention The present invention relates generally to an unspooling mechanism for continuous filaments and more specifically to a device which simultaneously unwinds and untwists twisted continuous filaments from a spool.

2. Description of the Prior Art There are many known or anticipated uses for high tensile strength, highly flexible yarns. Such yarns may be formed of synthetic plastic filaments or metal filaments and be adapted to be woven into suitable textile materials such as sheets or strips, or to be embedded or otherwise disposed in other materials such as for reinforcing the same, providing antistatic characteristics,

etc.

In one known method of forming yarns with metal filaments, a plurality of metal filaments are disposed in parallel spaced relationship with a matrix material extending between the respective filaments. The bundle of filaments is radially constricted, such as by drawing of the bundle through a drawing die whereby the individual filaments and the matrix are reduced in diameter. To obtain the desired filament diameter multiple drawing steps may be required. The final constricted bundle is then simply treated to remove the matrix material from the small diameter filaments, thereby providing a yarn comprised of a plurality of fine filaments. To provide the desirable yarn characteristics, it is common to provide in such yarns the twist of a number of turns per inch. One conventional method of applying a twist to the metal filaments is to feed each of the filaments individually to a twisting apparatus which wraps the filaments around each other in general helical fashion. A more advanced method for providing a twisted metal filament without the resulting residual torsion forces is disclosed in US. Pat. Nos. 3,378,999; 3,503,200; and 3,601,970, all owned by the assignee hereof.

The continuous filament yarn or tow is generally stored upon a spool for later use in blending devices. The bundles of filaments are usually stored twisted so as to retain the structural stability of the bundles after the removal of the matrix material. Industry has experienced great difficulty in unwinding the twisted material from the spools for use in blending devices. As the bundle filaments are unwound, the twist usually backs up from the guides so that untwisted segments of a bundle are fed through the blending machine and then segments of an unusual multitude of twists per unit length are fed to the blending machine. A variation from no twist to a high degree of twist produces uneven blending and results in an unacceptable number of slubs.

The blending industry is faced with a two-sided problem, namely, that it is well known that a metal filament bundle having twist is easier to unspool, yet untwisted filament bundles produce blended yarns with fewer slubs. Such metal filaments hold well in a blend due to their rough surfaces, however, just such a surface contributes to the difficulty in breaking into staple for blending. The present device and method achieves both desired results by simultaneously unwinding and untwisting the twisted filamment bundles just prior to introduction to the yarn guides of blending machines.

SUMMARY OF THE INVENTION Briefly, the present invention is a device and method for partially untwisting a twisted continuous filament tow during unwinding from the spool by rotating the spool about an axis at an angle relative to the longitudi nal axis of the spool about which the continuous filament bundle is unwinding. Preferably, the longitudinal axis of the spool is perpendicular to the axis of untwisting rotation and the midpoint of the longitudinal axis of the spool lies on the axis of untwisting rotation. The untwisting rotation can be produced by a motor-driven shaft and the unwinding rotation is produced by the force exerted by a textile machine drawing on the continuous filament. An eyelet through which the unwinding continuous filament passes rests on a support secured to and rotating with the motor-driven shaft. The eyelet is provided with a surface which withstands the abrasion of a metallic continuous filament. The spool is mounted to rotate freely on a second support, which is also mounted to the motor-driven shaft. Once the group of parallel, continuous filaments are in an untwisted tow form, it is possible to continuously form sliver therefrom or staple fibers for blending as taught in US. Pat. No. 3,678,675 without the formation of slubs.

OBJECTS OF THE INVENTION An object of the present invention is to provide an untwisting device for a spool mounted twisted continuous filament tow.

Another object of the invention is to provide a method and device for simultaneously untwisting and unwinding a twisted continuous filament bundle.

Another object of the invention is to provide an unwinding device which minimizes the formation of slubs in a blending process using bundles of continuous metal filaments.

Still another object is to provide a combination untwisting and unwinding device which will not substantially increse the cost of production by requiring expensive and time consuming process steps.

Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawmgs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic layout of an example apparatus depicting the problems of the prior art;

FIG. 2 is a schematic layout of the apparatus and the method for carrying out the present invention;

FIG. 3 is a perspective view of the apparatus of the present invention;

FIG. 4 is a perspective view of another embodiment of the apparatus of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 depicts the problem of the prior art wherein it is desired to blend a continuous filament 10, such as continuous metal filaments, with an organic fiber sliver 12 in a machine represented generally by the introductory rolls l4 and 16. The continuous filament, which may be a bundle of filaments produced by the previously mentioned patents owned by the assignee herein,

are stored in twisted configuration upon a spool 18. The continuous filaments 10 are drawn from a spool 18 through a guide 20 to the rolls l4 and 16. Examples of methods of blending from rolls 14 and 16 can be found in US. Pat. No. 3,678,675, owned by the assignee. As is explicitly shown in FIG. 1, the twist of continuous filament 10 is pushed back from guide 20 so that initially the filament 10 has little or no twist upon entering the rolls l4 and 16. At a later point in time, the pushed back twist will present a highly twisted or an enormous number of twist per unit length filament to the rolls l4 and 16. This variance in the amount of twist per unit length of the continuous filament 10 results in uneven breaking of continuous filament l and produces unacceptable slubs in the blended yarn.

One solution to the problem is to untwist the contents of roller 18 and store the continuous filament on a second roll in the untwisted state. But as discussed previously, it is difficult to unwind the untwisted filament from a spool for processing in yarn blending machines and the bundles of continuous filaments will sag if they are not stored in a twisted condition. When the filaments are metal their rough outer surfaces also cause the filaments to snag. Thus, the present invention provides a simultaneously unwinding and untwisting of a continuous filament, preferably stored twisted on a spool.

The untwisting machine of the present invention is schematically shown in FIG. 2 as 22 and provides a partially untwisted filament 24 to a guide 26 which also receives two organic fiber slivers 28 and 30 which are blended by a machine represented generally by rollers 32 and 34. Though the untwisting device 22 of the present invention is shown in FIG. 2 as providing a substantially untwisted continous filament 24 to a drawing frame, represented by rollers 32 and 34 and guide 26, the untwister ofthe present invention may also be used with wool cards and spinning frames and other yarn production devices as well.

In one preferred embodiment of the invention the untwister has a motor 36 with a transmission or gearing device 38 which drives rotating shaft 40. Control 41 determines the gear ratio of gearing device 38 so as to adjust the speed of rotating shaft 40. Secured at one end of shaft 40 is a generally L-shaped support 42 to which is mounted, on a bearing surface 44, a shaft 46 upon which is mounted a spool 48 of twisted continuous filaments. Also mounted to rotating shaft 40 is another L- shaped support 50 to which an eyelet 52 is attached by a member 54 and securing devices 56. The continuous filament 24 is drawn from spool 48 through eyelet 52 and an insert or coating 58 is provided in eyelet 52 to withstand the abrasive character of a metallic continuous filament 24. The insert or coating may be an aluminum oxide-ceramic compound (for example, Henium or Alsimag) but any other suitable material which will reduce abrasion is acceptable.

. The driven shaft 40 defines an axis of rotation about which the longitudinal axis of spool 48 is rotated. This rotating motion provides the untwisting effect of the present invention. Simultaneously with the untwisting motion of shaft 40. support 42, and spool 48, the continuous filament 24 is drawn through eyelet 52, thus resulting in a rotation of the spool 48 around its longitudinal axis to produce unwinding. To stabilize the untwister 22 and reduce extraneous moments, all the supports and elements of the present device are centered around the axis of rotation of shaft 40. Thus, the support 42 is shaped such that the axis of rotation of shaft 40 intersects the mipoint of longitudinal axis of the spool. lt shouldl also be noted that eyelet 52 is centered upon the axis of rotation of shaft 40. This positioning of the eyelet maintains the longitudinal axis of an unwound portion of the continuous filament 24 parallel to and at times coincident with the axis of rotation ofshaft 40.

The same relationship of the spool 48 and its longitudinal axis to the axis rotation of shaft 40 is maintained by mounting support 42 directly to support 50 as shown in FIG. 4. Though requiring a stronger support 50 and creating greater moments of inertia, the modification as depicted in FIG. 4 does produce acceptable results.

Though support 42 has been shown in both preferred embodiments to be L-shaped such that the longitudinal axis of the spool 48 is perpendicular to the axis of rotation of shaft 40, the angular relationship of these two axes may be varied. For maximum stability, it is suggested that the midpoint of the longitudinal axis of spool 48 lie on the axis of rotation of shaft 40 even though the angular relationship between these two axes is not orthogonal. Similarly, eyelet 52 need not intersect the axis of rotation of shaft 40 but may lie anywhere. The choice of the location of eyelet 52 was to minimize the moments of inertia due to rotation of the support 50 and reduce the interaction to the continuous filament 24 and eyelet 52.

The method and apparatus of the present invention were found to be most effective with bundles of metal filaments containing greater than 600 filaments per bundle. The unspooling and untwisting of bundles above 600 has produced the greatest problem in the industry. The present invention has been used with a two of 1,159 filaments of 8 micron diameter stainless steel having a twist of halfa turn per inch. These bundles are mounted on a 6-inch long spool having an inside diameter of 2 inches and an outside diameter, with the bundles wrapped thereon, of approximately 2 4 inches. As stated earlier, it is desirable to untwist the filament bundles to open up the filaments for proper blending so as to prevent uneven breaking which can cause slubbing. Using the twisted spool bundles just described, the spools longitudinal axis was rotated one revolution for each revolution of the spool around its longitudinal axis so as to untwist the filament bundles by approximately 30%. This one-to-one relationship has been found to be satisfactory in reducing the number of slubs appearing in the blended yarn. With bundles of smaller number of filaments having generally more twist per inch, the number of revolutions of a spindles longitudinal axis will generally have to be increased so as to provide a continuous filament bundle 24 which will result in a minimum amount of slubs. It is fully contemplated that a device comprising a plurality of untwisting devices can be arranged so that only one motor is required.

Although the invention has been described and illustrated in detail, it is to be clearly understood that the same is by of way of illustration and example only and is not to be taken by way of limitation, the scope and spirit of the invention being limited only by the terms of the appended claims.

What is claimed is:

l. A method of unwinding and untwisting a tow of filaments from a spool comprising the steps of:

unwinding said filaments by rotating said spool about its longitudinal axis; untwisting said filaments by rotating said spool about a second axis; and

controlling the relative speeds of the unwinding and the untwisting to provide a substantially open and loose filament tow band that is capable of being broken into staple fiber form.

2. The method of claim 1 wherein said spool is rotated a revolution about said second axis for every revolution about said longitudinal axis.

3. A method of unwinding and untwisting a tow of filaments from a spool comprising the steps of:

unwinding said filaments by rotating said spool about its longitudinal axis; and

untwisting said filaments by rotating said spool about a second axis, said spool is rotated a revolution about said second axis for every revolution about said longitudinal axis and said tow is twisted a half a turn an inch and is untwisted about 30%.

4. A method as in claim 3 wherein said tow is a composite of greater than 600 filaments.

5. A method as in claim 1 wherein said unwinding is produced by drawing said filaments and said untwisting is produced by a motor rotating said spool about said second axis.

6. A method as in claim 1 wherein said second axis is perpendicular to said longitudinal axis.

7. A method of untwisting a twisted continuous filament tow being unwound from a spool comprising the step of rotating said spool about a first axis at an angle to the axis about which said filament is being unwound, wherein said tow is being unwound by being drawn into a subsequent blending operation and is being rotated about said first axis by a driving means.

8. A method as in claim 7 wherein said first axis is perpendicular to said axis of unwinding.

9. An apparatus for untwisting a twisted continuous filament tow wound upon a spool comprising:

first means for producing rotation about a first axis;

second means attached to said first means for main taining the longitudinal axis of said spool at an angle to said first axis;

wherein said spool is mounted on said second means for rotation with said second means about said first means; and

means for controlling the relative rotations of said first and second means to provide a substantially open and loose filament tow band.

10. An apparatus as in claim 9 wherein said spool is mounted to said second means for rotation about said spools longitudinal axis.

11. An apparatus as in claim 10 including third means secured to said first means for maintaining the longitudinal axis of an unwound portion of said tow parallel to said first axis.

12. An apparatus as in claim 11 wherein said third means includes an eyelet through which filament tow passes.

13. An apparatus for untwisting a twisted continuous filament tow wound upon a spool comprising:

first means for producing rotation about a first axis;

second means attached to said first means for maintaining the longitudinal axis of said spool at an angle to said first axis and rotates about the spools longitudinal axis; and third means secured to said first means for maintaining the longitudinal axis of an unwound portion of said tow parallel to said first axis and including an eyelet through which said filament tow passes, said eyelet having an insert to prevent abrasion of said filament tow. 14. An apparatus as in claim 9 wherein said second means maintains said spools longitudinal axis perpendicular to said first axis.

15. An apparatus as in claim 9 wherein said second means maintains the midpoint of said spools longitudinal axis on said first axis.

16. An apparatus for untwisting a twisted continuous filament tow wound on a spool comprising:

first means for rotating said spool about a first axis at an angle to the longitudinal axis of said spool;

second means for rotating said spool about said longitudinal axis whereby said spool is untwisted and unwound simultaneously; and

means for controlling the relative rotation of said first and second means to provide a substantially open and loose filament tow band.

17. An apparatus as in claim 16 wherein said first means includes a first support means on which said spool is mounted for free rotation about said longitudinal axis.

18. An apparatus as in claim 17 wherein said first means includes a rotating shaft whose axis of rotation is said first axis and said first support means is mounted to said shaft, whereby rotation of said shaft rotates said spools longitudinal axis about said first axis.

19. An apparatus as in claim 18 wherein said first support means is L-shaped whereby said spools longitudinal axis is perpendicular to said first axis.

20. An apparatus as in claim 19 wherein said first support means maintains the midpoint of said spools longitudinal axis on said first axis.

21. An apparatus for untwisting continuous filament tow wound on on a spool comprising:

first means for rotating said spool about a first axis which is perpendicular to the longitudinal axis of the spool, said means including a rotating shaft whose axis of rotation is identical to said first axis. said spool mounted for free rotation on an L- shaped means supported by said first means and mounted on said shaft;

means for maintaining the mid-point of said spools longitudinal axis on said first axis; and

an eyelet through which said unwinding filaments pass and mounted on a bracket secured to said rotating shaft.

22. An apparatus as in claim 21 wherein said filaments are metallic and said eyelet includes a surface to prevent abrasion of said metallic filaments.

23. An apparatus as in claim 21 wherein said eyelet intersects said first axis.

24. An apparatus as in claim 18 wherein said second means is a yarn processor which draws said continuous filament tow. 

1. A method of unwinding and untwisting a tow of filaments from a spool comprising the steps of: unwinding said filaments by rotating said spool about its longitudinal axis; untwisting said filaments by rotating said spool about a second axis; and controlling the relative speeds of the unwinding and the untwisting to provide a substantially open and loose filament tow band that is capable of being broken into staple fiber form.
 2. The method of claim 1 wherein said spool is rotated a revolution about said second axis for every revolution about said longitudinal axis.
 3. A method of unwinding and untwisting a tow of filaments from a spool comprising the steps of: unwinding said filaments by rotating said spool about its longitudinal axis; and untwisting said filaments by rotating said spool about a second axis, said spool is rotated a revolution about said second axis for every revolution about said longitudinal axis and said tow is twisted a half a turn an inch and is untwisted about 30%.
 4. A method as in claim 3 wherein said tow is a composite of greater than 600 filaments.
 5. A method as in claim 1 wherein said unwinding is produced by drawing said filaments and said untwisting is produced by a motor rotating said spool about said second axis.
 6. A method as in claim 1 wherein said second axis is perpendicular to said longitudinal axis.
 7. A method of untwisting a twisted continuous filament tow being unwound from a spool comprising the step of rotating said spool about a first axis at an angle to the axis about which said filament is being unwound, wherein said tow is being unwound by being drawn into a subsequent blending operation and is being rotated about said first axis by a driving means.
 8. A method as in claim 7 wherein said first axis is perpendicular to said axis of unwinding.
 9. An apparatus for untwisting a twisted continuous filament tow wound upon a spool comprising: first means for producing rotation about a first axis; second means attached to said first means for maintaining the longitudinal axis of said spool at an angle to said first axis; wherein said spool is mounted on said second means for rotation with said second means about said first means; and means for controlling the relative rotations of said first and second means to provide a substantially open and loose filament tow band.
 10. An apparatus as in claim 9 wherein said spool is mounted to said second means for rotation about said spool''s longitudinal axis.
 11. An apparatus as in claim 10 including third means secured to said first means for maintaining the longitudinal axis of an unwound portion of said tow parallel to said first axis.
 12. An apparatus as in claim 11 wherein said third means includes an eyelet through which filament tow passes.
 13. An apparatus for untwisting a twisted continuous filament tow wound upon a spool comprising: first means for producing rotation about a first axis; second means attached to said first means for maintaining the longitudinal axis of said spool at an angle to said first axis and rotates about the spool''s longitudinal axis; and third means secured to said first means for maintaining the longitudinal axis of an unwound portion of said tow parallel to said first axis and including an eyelet through which said filament tow passes, said eyelet having an insert to prevent abrasion of said filament tow.
 14. An apparatus as in claim 9 wherein said second means maintains said spools longitudinal axis perpendicular to said first axis.
 15. An apparatus as in claim 9 wherein said second means maintains the midpoint of said spool''s longitudinal axis on said first axis.
 16. An apparatus for untwisting a twisted continuous filament tow wound on a spool comprising: first means for rotating said spool about a first axis at an angle to the longitudinal axis of said spool; second means for rotating said spool about said longitudinal axis whereby said spool is untwisted and unwound simultaneously; and means for controlling the relative rotation of said first and second means to provide a substantially open and loose filament tow band.
 17. An apparatus as in claim 16 wherein said first means includes a first support means on which said spool is mounted for free rotation about said longitudinal axis.
 18. An apparatus as in claim 17 wherein said first means includes a rotating shaft whose axis of rotation is said first axis and said first support means is mounted to said shaft, whereby rotation of said shaft rotates said spool''s longitudinal axis about said first axis.
 19. An apparatus as in claim 18 wherein said first support means is L-shaped whereby said spool''s longitudinal axis is perpendicular to said first axis.
 20. An apparatus as in claim 19 wherein said first support means maintains the midpoint of said spool''s longitudinal axis on said first axis.
 21. An apparatus for untwisting continuous filament tow wound on on a spool comprising: first means for rotating said spool about a first axis which is perpendicular to the longitudinal axis of the spool, said means including a rotating shaft whose axis of rotation is identical to said first axis, said spool mounted for free rotation on an L-shaped means supported by said first means and mounted on said shaft; means for maintaining the mid-point of said spool''s longitudinal axis on said first axis; and an eyelet through which said unwinding filaments pass and mounted on a bracket secured to said rotating shaft.
 22. An apparatus as in claim 21 wherein said filaments are metallic and said eyelet includes a surface to prevent abrasion of said metallic filaments.
 23. An apparatuS as in claim 21 wherein said eyelet intersects said first axis.
 24. An apparatus as in claim 18 wherein said second means is a yarn processor which draws said continuous filament tow. 